Otis Adelbert Kline (1891–1946) born in Chicago, Illinois, USA, was an adventure novelist and literary agent during the pulp era. Much of his work first appeared in the magazine Weird Tales. Kline was an amateur orientalist and a student of Arabic, like his friend and sometime collaborator, E. Hoffmann Price

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"You will feel an urge to go to a certain place tonight which you may or may not have been planning to go to, and you will want to get there around 8 p.m. Starting at 8:30 p.m., every half hour, I will send you a message. You may not hear it the first or second time, but you may feel distracted. If you are the man I want, it will seem as if a voice is speaking to you. It will be a voice in your mind; it will say `Doctor Morgan' and direct you to go to a particular spot. There a man will be waiting for you; he will ask you a question which I shall also tell you of when I communicate with you. Please give him a hearing before you decide."